Light-sensitive color photographic film



1954 P. RAIBOURN 2,667,414

LIGHT-SENSITIVE COLOR PHOTOGRAPHIC FILM Original Filed April 29, 1947 EMULS/OA/ ovsa YEL LOW THROUGHOUT I flA/oJasrRncr/vE COLOR 1742006110411 CONCENTRfiT/O/V 9PM R50, GREEN 9ND BLUE SENSITIVE RED END GREEN SEA/.57 Tl vE III "I I lllll IP50 g? GREEN SENSITIVE JuPPoR 7 w Pazzl'RaiEcurn HIS ATTORNEYS,

Patented Jan. 26, 1954 TJNT OFFICE 2,667,414 LIGHT-SENSITIVE CgLLBQRfPHOTOGRAPHIC Paul Raibourn, Southport, Conn.

Original application April29, 1947, Serial No.

744,771, now Patent No. 2,628,902, dated 'Feb- .ruary 17, .1953. Divided and this application June 29, 1948, Serial No. 35,972

' 3 Claims. l

This invention=relates to color'photography,

and is characterized by the production of a satisfactory and approximately correct rendition of the original subject, having a plurality of superposed color images, preferably three, in a single 'light sensitive emulsion.

Themany objects and advantages of this invention will be apparent from the following de tailed description of the method comprising it.

This invention resides substantially in the steps This'application is a'division of my copending application Serial No. 744,771, filed Apri 29, 1947,

therein of multicolor separations in superposed registered relation.

-Asan example-but Without desiring to be lim-- ited thereby, the thickness of the 'film will be such that the film when processed as hereinafter specified is capable of a blue shadow density of 2. The emulsion is dyed throughout with a yellow dye of a high concentration, and is then dyed with a magentadye in a concentrationoneehalf of that of the yellow. Other concentrations'of 'themnagenta dye, less'thanthat of the yellow,

may be used. .As. a criterion, asto the concentrationof the, yellowdye tobe used, thisconcentration; should be just sufficient to confine the blue portion, as determined by a -Wratten C5 filter, ofa difiusedwhite highlight, in theupper third of the emulsion. .-As will app-ear, as the description proceeds, theusingle emulsion layer is divided in the process into-.threeimag-inary layers, inv a directionatright angles/to the plane of thefilm. Suchstratification could also be produced by controlled penetration of dyes into the emulsion in wel known manners. The term "selective dyeing-as used herein includes dyeing throughout with dyesot two difierent subtractive, primary'colors, or. dyeing'throughout with I one of said colors and to a controlled depth with the other, or dyeing to approximately thesame controlled depth with both of said colors, or dyeing tov different. depths with-each of the colors, the depths being preferably, but not. necessarily, multiples of one-third of the thickness of the emulsion. As an example; some of the basic dyes or dyes used in the wash-ofi relief process can beusedrior this purpose. The magentadye may be: replacedby cyan dye-"in which case therelaand seriesof steps as herein described, and the products thereof.

panchromatic filmfor the formation directly processes less image: Gb and Rb.

tive position ofithe-finalcyan andmagentaimages, in-position and processing, willbe reversed.

Such a film isproperly exposed as is all reversal .color film to the scene to be photographed whereupon it will have latent imagesas follows:

i 1. The upper (outer) third of the emulsion will 'contain a latent-image composed ofa blue component Bbgagreen component Gb and ared component Rb plus other unexposed silver halide.

2. The next (middle) third imaginary layer 0f thefilm will containqalatent image composed of a' green component Gig and a-red component Rg plus other-unexposed silver halide. This results since the yellow has confined the blue image to the upper layer-and the magenta confined the green to the upper' A ofthe total emulsion.

3. The last (adjacent the base) third imaginary layer of the film-will containa latent image composed' of a' red component. RT; plus othernnexposed silver halide.

The relation of the depth of the images in the various imaginary layers may be controlled by varying the concentration of the dyes in the emulsion.

The process in generalmay-be understoodif a summary description is given of. how the yellow (minus blue) image is obtained.

This exposed film is processed so that the upper third or outer layer'is developed by..controlled penetration, usinga developer, such as. Eastman D476 or DK-.-50. In this layer, there results, a black and white negative image made up of the components Bb, +Gb and Rh, as a negative.

If theremainder of the silver halide in this imaginary uppenlayeris' exposed to light where the penetration of .the light is limited to the upper layer by dye, or other Well known means, and then developed to color with a yellow coupler dye, in a well known manner, .there would be produced a 'desire'd yellow ,subtractiverimage as is commonly produced in several well known color If ,Gbequals Gg'and Rb equals Rg, and if the exposed silver halide (latent image) .of .the seoond'layer also 7 .istdeveloped by controlled penetration with'a the yellow image, the process is to expose the film and develop the latent image of the outer imaginary layer, by controlled penetration, to a black and white silver image, as explained above. The outer layer is then exposed with sufficient light, controlled by dye or other means, preferably ultra-violet or blue light, so it is developable using a developer which by controlled penetration develops the latent images in the second layer at the same time. This development may be carried out by well known toning, direct development, or coupler procedures to develop the latent reversal image in the outer layer to silver along with a yellow image and the latent image in the middle layer to silver and yellow.

Wherever development to a color is specified herein it may be either by the well known processes of toning, direct color development or coupler color development.

In the second layer at this stage of the process, there is unexposed and undeveloped silver halide which is the desired reversal positive to be colored magenta minus Rg. If we now develop latent image R7, which is equal to R9, to a magenta then we have in total the desired reversal magenta image. The lower imaginary layer adjacent the base is exposed through th base by light controlled in its penetration to that layer and developed to silver and cyan which is the desired cyan component.

All the remaining silver halide in the middle layer is then exposed to light and this image is then developed to silver and magenta in the usual manner.

All the silver now in the emulsion is then removed with Farmers reducer.

There thus results a perfect reproduction of the original scene in full color provided the density matrix of the dyes which form the color images is as follows:

Cyan Magenta Yellow ooo The followin is given as a somewhat more graphic illustration of the process described above. The original latent image as explained, in the three imaginary layers contains the following components:

B b Gb RB outer layer Ga Rg middle layer Rr final layer Silver (Bb Gb Rb) lBb-Gb-Rb Silver halide ..lGg-Rg +Gb+Rb l-Bb Silver and yellow The latent image in the inner layer is then developed to silver and magenta.

The lower layer i then exposed through the base by controlled light penetration and devel- Can oped to silver and cyan which can be illustrated symbolically as:

Cyan=1-Rr The remaining silver halide in the middle layer is then exposed and developed to silver and magenta giving the following result graphically:

1-GgR We now have magenta images of:

Rr to magenta eifa 'g vii i325 T It is helpful in the foregoing example that the green record images in the upper layer and the middle layer be approximately equal and the red record images in all three layers be approximately equal. These can be equalized by varying the inertia and contrast characteristics of the various developers used by increasing the alkalinity, changing their characteristics by silver halide solvents such as potassium thiocyanate or hypo or by restraining development by inhibitors such as potassium bromide.

It is also helpful that the light sensitive emulsion show a greater sensitivity for the image which will record in all three depths of the emulsion such as the red record image in the foregoing example. It is also helpful if the light sensitive emulsion show a greater sensitivity for the image which will record in two depths than that which will record in one depth. Such light sensitive emulsions are well known in commercial practice.

It Will be apparent to those skilled in the art that the above processing procedure can be modilied to correct any deviations from the above ideal color matrix so that masking can be effected by means of the dyes which exist in the various layers.

It will be assumed that the printin colors have the following density matrix for subtractive color as often approximately encountered in practice.

Cyan Magenta Yellow Bb Gb Rb The remaining silver halide of the outer layer is exposed to ultra-violet or blue light which due to dye or emulsion characteristics is confined to rendering the upper layer developable and developed to silver and yellow by controlled penetration. As a result of exposure the yellow image can be graphically illustrated as:

By control of penetration and time of development and developer characteristics the following silver and yellow images can be obtained for the existing latent image in the other layers:

+0.5+0.5 RgSecond layer +0.4 R1'Third layer The final result of this processing is that the yellow image in the layers is graphically represented as:

1-Bb-0 5 Gin-0.1 Rb

which was the desired yellow image.

The image in the middle layer is developed to silver (black and white) by controlled difiusion so that the following results:

The remaining latent image in the third layer is then developed to magenta having the value 0.6 R7. The film is then exposed through the base with a light which just renders the third layer developable and the third layer developed to silver and cyan which can be represented as 1-Rr. The remaining silver halide in the middle layer is then exposed and developed to silver and magenta and the result can be graphically represented as:

Second layer 1-GgRg Third layer .1 0.6 R1; if Rg=Rr Thus, it will be seen that by modifying the basic processing procedure corrections for deviations of the printing colors from the ideal can be made in the negatives so that in printing therefrom masking is automatically effected by means of the colored images which exist in the various layers.

It will also be realized that the principles disclosed herein will work just as well if the film is exposed through the base, the dyes in the emulsion serving as anti-halation dyes, and the processing being changed accordingly.

What is claimed is:

l. A photographic film comprising a base having applied thereto a single layer silver halide emulsion sensitive uniformly throughout its depth to panchromatic light, said silver halide emulsion layer being dyed to uniform concentration throughout with two subtractive primary coloring materials, one of which is yellow and the other of which is one of magenta and cyan, said other being present in one half the concentration of the yellow, said film being effective upon exposure of said emulsion to form therein three strata, each carrying a primary color separation, the uppermost stratum being characterized by its capacity to form red, green and blue latent images, the central stratum being characterized by its capacity to form red and green latent images and the lowermost stratum being characterized by its capacity to form a latent image of one of the colors red and green.

2. The film in accordance with claim 1, in which the subtractive colors are yellow and magenta, the magenta being present in about one-half the concentration of the yellow.

3. The article in accordance with claim 1, in which the dyes are yellow and cyan, the cyan being present in about one-half the concentration of the yellow.

PAUL RAIBOURN References Cited in the file of this patent UNITED STATES PATENTS Number Name Date Re. 18,680 Troland Dec. 6, 1932 1,677,665 Weaver July 17, 1928 1,804,727 Weaver May 12, 1931 2,020,607 Heymer Nov. 12, 1935 2,028,279 Gaspar Jan. 21, 1936 2,044,864 Troland June 23, 1936 2,219,304 Gaspar Oct. 29, 1940 FOREIGN PATENTS Number Country Date 340,278 Great Britain Dec. 17, 1930 

1. A PHOTOGRAPHIC FILM COMPRISING A BASE HAVING APPLIED THERETO A SINGLE LAYER SILVER HALIDE EMULSION SENSITIVE UNIFORMLY THROUGHOUT ITS DEPTH TO PANCHROMATIC LIGHT, SAID SILVER HALIDE EMULSION LAYER BEING DYED TO UNIFORM CONCENTRATION THROUGHOUT WITH TWO SUBSTRACTIVE PRIMARY COLORING MATERIALS, ONE OF WHICH IS YELLOW AND THE OTHER OF WHICH IS ONE OF MAGENTA AND CYAN, SAID OTHER BEING PRESENT IN ONE HALF OF THE CONCENTRATION OF THE YELLOW, SAID FILM BEING EFFECTIVE UPON EXPOSURE OF SAID EMULSION TO FORM THEREIN THREE STRATA, EACH CARRYING A PRIMARY COLOR SEPERATION, THE UPPERMOST STRATUM BEING CHARACTERIZED BY ITS CAPACITY TO FORM RED, GREEN AND BLUE LATENT IMAGES, THE CENTRAL STRATUM BEING CHARACTERIZED BY ITS CAPACITY TO FORM RED AND GREEN LATENT IMAGES AND THE LOWERMOST STRATUM BEING CHARACTERIZED BY ITS CEAPACITY TO FORM A LATENT IMAGE OF ONE OF THE COLORS RED AND GREEN. 